Nectarine tree, ‘Burnectwenty’

ABSTRACT

A new and distinct variety of nectarine tree  Prunus persica , and which is denominated varietally as ‘Burnectwenty’, and which produces an attractively colored yellow-fleshed, clingstone, nectarine which is mature for harvesting approximately September 13 to September 23 under ecological conditions prevailing in the San Joaquin Valley of central California.

Botanical designation: Prunus persica.

Variety denomination: Burnectwenty.

BACKGROUND OF THE NEW INVENTION

The present invention relates to a new, novel and distinct variety ofnectarine tree, Prunus persica, and which has been denominatedvarietally as ‘Burnectwenty’ hereinafter.

The present variety of nectarine tree resulted from an on-going programof fruit and nut tree breeding. The purpose of this program is toimprove the commercial quality of deciduous fruit and nut varieties, androotstocks, by creating and releasing promising selections of Prunus,Malus, and Regia species. To this end we make both controlled and hybridcross pollinations each year in order to produce seedling populationsfrom which improved progenies are evaluated and selected.

The seedling, ‘Burnectwenty’, was originated by us from a population ofseedlings grown in our experimental orchards located near Fowler, Calif.The seedlings, grown on their own roots, were the result of seeds whichwere derived from an open pollinated seedling, B17.074 (unpatented).B17.074 was the result of a previous cross of the yellow-fleshedclingstone nectarine tree ‘September Red’ (U.S. Pat. No. 5,664), whichwas used as the seed parent; and the ‘Grant Diamond’ nectarine (U.S.Plant Pat. No. 4,095) which was used as the pollen parent. The openpollination of B17.074 occurred sometime during March 1998. Thereafterseeds from this open pollinated seedling were collected and then plantedin September of 1998. One seedling, identified as I 9.076, which is thepresent variety, exhibited especially desirable characteristics, and wasmarked for subsequent observation. After the 2000 fruiting season, thenew variety of nectarine tree was selected for advanced evaluation andrepropagation.

ASEXUAL REPRODUCTION

Asexual reproduction of this new and distinct variety of nectarine treewas accomplished by budding the new nectarine tree to ‘Nemaguard’Rootstock (unpatented). This was performed by us in our experimentalorchard which is located near Fowler, Calif. Subsequent evaluations haveshown those asexual reproductions run true to the original tree. Allcharacteristics of the original tree, and its fruit, were establishedand appear to be transmitted through succeeding asexual propagations.

SUMMARY OF THE VARIETY

‘Burnectwenty’ is a new and distinct variety of nectarine tree, which isconsidered of large size, and which has vigorous growth. This newnectarine tree is also a regular and productive bearer of relativelylarge, firm, yellow fleshed, acidic clingstone fruit which have a goodflavor and eating qualities. This new tree has a medium chillingrequirement of approximately 650 hours, and further produces relativelyuniformly sized fruit throughout the tree. In addition, the fruit alsoappears to have good handling and shipping qualities. Still further, the‘Burnectwenty’ nectarine tree bears fruit which are ripe for commercialharvesting and shipment on approximately September 13 to September 23under the ecological conditions prevailing in the San Joaquin ValleyCentral California. In relative comparison to the seed parent, B17.074,the present nectarine tree bears fruit about 10 or more days earlier atthe same geographical location. In comparison to the ‘Grand Diamond’nectarine tree, the present variety produces a clingstone fruit, whereas‘Grant Diamond’ produces freestone fruit. In relative comparison toother known varieties, the present variety of nectarine tree is mostclosely similar to the ‘September Bright’ Nectarine (U.S. Plant Pat. No.13,475), which, when grown in its natural state, produces fruit thatripen on or about September 1st, whereas the present new varietyproduces fruit which has a ripening date of September 13 or later.

BRIEF DESCRIPTION OF THE DRAWING

The accompanying drawing, is a color photograph of the present variety.The photograph depicts two whole mature fruit, and several pieces ofsliced fruit dissected substantially in the sagital plane, and one pieceof fruit taken from a cross sectional position. The external colorationof the fruit, as shown, as well as the exposed flesh segments, displayfruit which are sufficiently matured for harvesting and shipment.Additionally, the photograph displays a sample vegetative shoot bearingtypical leaves, and a stone, with the flesh removed. The colors in thisphotograph are as nearly true as is reasonably possible in a colorrepresentation of this type. Due to chemical development, processing andprinting, the leaves and fruit depicted in these photographs may or maynot be accurate when compared to the actual specimen. For this reason,future color references should be made to the color plates (RoyalHorticultural Society) and other more general color descriptionsprovided hereinafter.

DETAILED DESCRIPTION

Referring more specifically to the pomological details of this new anddistinct variety of nectarine tree, the following has been observedduring the fourth fruiting season under the ecological conditionsprevailing at orchards which are located near the town of Fowler, countyof Fresno, state of California. All major color code designations are byreference to The R.H.S. Colour Chart (Fourth Edition) and which isprovided by The Royal Horticultural Society of Great Britain. Commoncolor names are also occasionally used.

-   Tree:    -   -   Size.—Generally — Considered medium-large as compared to            other common commercial nectarine cultivars ripening in the            early season of maturity. The tree of the present variety            was pruned to a height of approximately 300.0 cm to about            310.0 cm at maturity.        -   Vigor.—Considered moderately vigorous. The present nectarine            tree variety grew from about 130.0 cm to about 135.0 cm in            height during the first growing season. The new variety was            pruned to a height of approximately 125.0 cm during the            first dormant season, and primary scaffolds were then            selected for the desired tree structure.        -   Productivity.—Productive. Fruit set varies from about 1.5 to            several times more than the desired crop load. Fruit set is            spaced by thinning to develop the remaining fruit into the            desired market sized fruit. The number of the fruit set            varies with the prevailing climatic conditions, and cultural            practices employed, and is therefore not distinctive of the            present variety.        -   Bearer.—Regular. Fruit set has been heavy during the years            of observation and thinning was necessary during the past 5            years.        -   Form.—Upright, and pruned to a vase shape.        -   Density.—Considered medium dense. It has been discovered            that pruning the branches from the center of the tree to            obtain a resulting vase shape allows for air movement and            appropriate amounts of sunlight to enhance fruit color and            renewal of fruiting wood throughout the tree.        -   Hardiness.—The present tree was grown and evaluated in USDA            Hardiness Zone 9. Winter chilling requirements of the new            tree are approximately 700 hours below 7.0 degrees C. The            variety appears to be hardy under typical central San            Joaquin Valley climatic conditions.-   Trunk:    -   -   Diameter.—Approximately 12.5 cm in diameter when measured at            a distance of approximately 15.24 cm above the soil level.            The measurement was taken at the end of the fifth growing            season.        -   Bark texture.—Considered moderately rough, with numerous            folds of papery scarfskin being present.        -   Lenticels.—Numerous flat, oval lenticels are present. The            lenticels are relatively large, and range in size from            approximately 4.0 to about 6.0 millimeters in width, and            from 1.0 to about 2.0 millimeters in height.        -   Lenticel color.—Orange brown, (RHS Greyed-Orange Group N170            A).        -   Bark coloration.—Variable, but it is generally a medium            grey-brown, (RHS Greyed-Orange Group 175 B).-   Branches:    -   -   Size.—Considered medium for the variety.        -   Diameter.—Average as compared to other nectarine varieties.            The branches have a diameter of about 5.9 centimeters when            measured during the third year after grafting.        -   Surface texture.—Average, and appearing furrowed on wood            which is several years old.        -   Crotch angles.—Primary branches are considered variable, and            are between about 48 to 55 degrees when measured from the            horizontal axis. This particular characteristic is not            considered distinctive of the variety, however.        -   Current season shoots.—Surface texture — Substantially            glabrous.        -   Internode length.—Approximately 2.3 to about 2.5 cm.        -   Color of mature branches.—Medium brown, (RHS Greyed-Orange            177 C).        -   Current seasons shoots.—Color — Light green, (RHS Green            Group 137 B). The color of new shoot tips is considered a            bright and shiny green (RHS Green Group 143 C).-   Leaves:    -   -   Size.—Considered medium for the species. Leaf measurements            have been taken from vigorous, upright, current-season            growth, at approximately mid-shoot.        -   Leaf length.—Approximately 140.0 to about 165.0 millimeters.        -   Leaf width.—Approximately 30.0 to about 35.0 millimeters.        -   Leaf base shape.—Slightly oblique relative to the leaf            longitudinal axis.        -   Leaf form.—Lancelolate.        -   Leaf tip form.—Acuminate.        -   Leaf color.—Upper Leaf Surface — Dark green, (approximately            RHS Yellow-Green Group 146 A).        -   Leaf texture.—Glabrous.        -   Leaf color.—Lower Surface — Medium green, (RHS Yellow-Green            Group 146 B).        -   Leaf venation.—Pinnately veined.        -   Mid-Vein.—Color — Light yellow green, (RHS Yellow-Green            Group N144 C).        -   Leaf margins.—Slightly undulating.        -   Form.—Considered crenate.        -   Uniformity.—Considered generally uniform.        -   Leaf petioles.—Size — Considered medium-long. Length — About            6.0 to about 12.0 mm. Diameter — About 1.5 to about 2.0 mm.            Color — Pale green, (RHS Yellow-Green Group 144 B).        -   Leaf glands.—Size — Considered small. Approximately 1.0 mm            in length, and about 1.0 mm in height. Number — Generally            one gland per margin side. Occasionally two glands per            margin side may be found. Type — Reniform. Color — Pale            orange (RHS Orange Group 26 A).        -   Leaf stipules.—Size — Medium for the variety. Number —            Typically 2 per leaf bud, and up to 6 per shoot tip. Form —            Lanceolate in form, and having a serrated margin. Color —            Green, (RHS Green Group 143 C) when young, but graduating to            a brown color, (RHS Greyed-Orange group 166 C) with            advancing senescence. The stipules are considered to be            early deciduous.-   Flowers:    -   -   Flower buds.—Generally — The floral buds, depending upon the            stage of development, are approximately 7.0 millimeters            wide; about 11.0 millimeters long; conic in form; and            slightly appressed relative to the bearing shoot. Floral bud            dimensions are highly dependent upon the timing of the            measurements.        -   Flower buds.—Color — This characteristic is dependent upon            the proximity to the bloom. The bud scales are deep purple,            (approximately RHS Greyed-Purple Group N186 C). The buds are            considered hardy under typical central San Joaquin Valley            climatic conditions.        -   Hardiness.—No winter injury has been noted during the last            several years of evaluation in the central San Joaquin            Valley. The current variety has not been intentionally            subjected to drought or heat stress, and therefore this            information is not available.        -   Date of first bloom.—Feb. 28, 2004.        -   Blooming time.—Considered mid season in relative comparison            to other commercial nectarine cultivars grown in the central            San Joaquin Valley. The date of full bloom was observed on            Mar. 6, 2004. The date of bloom varies slightly with            climatic conditions and cultural practices.        -   Duration of bloom.—Approximately 9 days. This characteristic            varies slightly with the prevailing climatic conditions.        -   Flower type.—The variety is considered to have a showy type            flower.        -   Flower size.—Flower diameter at full bloom is approximately            41.0 to about 44.0 millimeters.        -   Bloom quantity.—Considered abundant.        -   Flower bud frequency.—Normally 1 or more flower buds appear            per node.        -   Petal size.—Generally — Considered medium-large for the            species. Length — Approximately 19.0 to about 21.0            millimeters. Width — Approximately 18.0 to about 20.0            millimeters.        -   Petal form.—Considered generally rounded.        -   Petal count.—Nearly always 5.        -   Petal texture.—Glabrous.        -   Petal color.—Light pink, approximately (RHS Red-Purple Group            62 D).        -   Fragrance.—Slight.        -   Petal claw.—Form — The claw is generally elongated, and has            a medium size when compared to other varieties. Length —            Approximately 9.0 to about 11.0 millimeters. Width —            Approximately 8.0 to about 9.0 millimeters. Petal Margins —            Generally considered reasonably uniform and smooth and            moderately undulate.        -   Petal apex.—Generally — The petal apices are generally            entire at the tip.        -   Flower pedicel.—Length — Considered medium-long, and having            an average length of approximately 3.0 to about 5.0            millimeters. Diameter — Considered average, approximately            3.0 millimeters. Color — A dull green, (RHS Yellow-Green            Group N144 A).        -   Floral nectaries.—Color — A dull orange, (RHS Greyed-Orange            Group 168 A).        -   Calyx.—Surface Texture — Generally glabrous. Color —            Brownish-red, (approximately RHS Greyed-Red Group 181 B).        -   Sepals.—Surface Texture — The surface has a short, fine            pubescent texture. Size — Average, and ovate in form. Color            — A deep brownish-red, (approximately RHS Greyed-Red Group            181 A).        -   Anthers.—Generally — Average in length. Color — Red to            reddish-orange dorsally, (approximately RHS Greyed-Red Group            179 A). Pollen Production — Pollen is abundant, and has a            yellow color, (approximately RHS Yellow-Orange Group 17 C).            The present variety is considered self-fruitful and does not            require a pollinator.        -   Filaments.—Size — Length is variable, approximately 15.0 to            about 18.0 millimeters long. Color — Light pink, (RHS            Red-Purple Group 65 D).        -   Pistil.—Number — Usually 1, rarely 2. Generally —            Medium-long in size. Length — Approximately 17.0 to about            20.0 millimeters including the ovary. Color — Pale lime            green, (approximately RHS Yellow-Green Group 145 C). Surface            Texture — The variety has a long glabrous pistil.-   Fruit:    -   -   Maturity when described.—Firm ripe condition (shipping            ripe). Date of first picking — Sep. 13th, 2004. Date of last            picking — Sep. 23, 2004. The date of harvest varies slightly            with the prevailing climatic conditions and fruit maturity            harvested for preferred market requirements.        -   Size.—Generally — Considered large, and uniform.        -   Average cheek diameter.—Approximately 70.0 to about 72.0            millimeters.        -   Average axial diameter.—Approximately 68.0 to about 71.0            millimeters.        -   Typical weight.—Approximately 280.0 grams. This            characteristic is highly dependent upon the prevailing            cultural practices, and therefore is not particularly            distinctive of the variety.        -   Fruit form.—Generally rounded. The fruit is generally            uniform in symmetry.        -   Fruit suture.—Occasionally one hemisphere is extended. No            apparent callousing or stitching exists along the suture            line.        -   Suture.—Color — This has a yellow background color,            (approximately RHS Yellow-Orange Group 19 C).        -   Ventral surface.—Form — Slightly indented.        -   Apex.—Rounded.        -   Base.—Generally retuse.        -   Stem cavity.—Generally uniform and rounded in shape, and            moderately deep. The average depth of the stem cavity is            about 9.0 mm. The average width of the stem cavity is about            16.0 mm.        -   Fruit skin.—Thickness — Considered medium in thickness, and            tenacious to the flesh. Texture — Glabrous. Occasional            speckling is usually noted toward the apex. Taste —            Non-astringent. Tendency to crack — None observed.        -   Color.—Blush Color — This blush color is generally red            (approximately RHS Orange-Red Group N35 B). The blush covers            approximately 45-55% of the fruit skin surface. The            percentage of the blush on the fruit skin surface can vary,            and is generally dependent upon the prevailing conditions            under which the fruit was grown. Ground Color — Yellow            orange, (approximately RHS Yellow-Orange Group 19 C).        -   Fruit stem.—Medium, approximately 6.0 to about 8.0            millimeters. Diameter — Approximately 2.0 to 3.0            millimeters. Color — Pale yellow-green, (approximately RHS            Yellow-Green Group 144 B).        -   Flesh.—Ripens — Evenly. Texture — Firm, juicy and dense. The            flesh is considered non-melting. Fibers — Few, small, and            tender ones are typically found. Aroma — Very slight. Eating            Quality — Considered very good. Flavor — Considered sweet            and slightly acidic. The flavor is considered both pleasant            and balanced. Juice — Moderate. Brix — About 15.0 degrees.            This characteristic varies slightly with the number of fruit            per tree; prevailing cultural practices; and the surrounding            climatic conditions. Flesh Color — Pale yellow-orange,            (approximately RHS Yellow-Orange Group 18 B).-   Stone:    -   -   Type.—Clingstone.        -   Size.—Considered medium for the variety. The stone size            varies significantly depending upon the tree vigor, crop            load and the prevailing growing conditions.        -   Length.—Average, about 29.0 to about 32.0 millimeters.        -   Width.—Average, about 22.0 to about 27.0 millimeters.        -   Diameter.—Average, about 17.0 to about 19.0 millimeters.        -   Form.—Generally ovoid.        -   Base.—The stone is usually ovoid basally.        -   Apex.—Shape — Generally the stone apex has a small prominent            tip.        -   Stone surface.—Surface Texture — Pitting, in general, is            more common than furrowing, which is typically noted near,            and is generally parallel with the ventral and dorsal edges.            Ridges — The surface texture is generally characterized by            more prominent ridges along the ventral margins. Ventral            Edge — Width — Considered medium, and having a dimension of            approximately 3.0 to about 4.0 millimeters when measured at            mid-suture. Dorsal Edge — Shape — Oblique toward the stem            end, and exhibiting a slight reduction of the margin toward            the base.        -   Stone color.—The color of the dry stone is generally reddish            brown, (approximately Greyed-Orange Group RHS 166 B).        -   Tendency to split.—Splitting has rarely been noted.        -   Kernel.—Size — The kernel is considered medium. Form —            Considered generally ovoid. Pellicle — Pubescent and ridging            is usually absent. Color — (RHS Greyed-Orange Group N167 C).        -   Use.—The subject variety ‘Burnectwenty’ is considered to be            a nectarine tree of the late season of maturity, and which            produces fruit that are considered firm, attractively            colored, and which are useful for both local and long            distance shipping.        -   Keeping quality.—Excellent. Fruit has stored well for up to            25 days after harvest at 1.0 degree Celsius.        -   Shipping quality.—Considered good. The fruit of the new            nectarine tree variety showed minimal bruising of the flesh,            or skin damage after being subjected to normal harvesting            and packing procedures.        -   Resistance to insects and disease.—No particular            susceptibilities were noted. The present variety has not            been tested to expose or detect any susceptibilities or            resistances to any known plant and/or fruit diseases.

Although the new variety of nectarine tree possesses the describedcharacteristics when grown under the ecological conditions prevailingnear Fowler, Calif., in the central part of the San Joaquin Valley ofCalifornia, it should be understood that variations of the usualmagnitude and characteristics incident to changes in growing conditions,fertilization, pruning, pest control and horticultural management are tobe expected.

1. A new distinct variety of nectarine tree substantially as illustratedand described, and which is characterized principally as to novelty byproducing an attractively colored yellow-fleshed, freestone, nectarinewhich is mature for harvesting approximately September 13 to September23 under the ecological conditions prevailing in the San Joaquin Valleyof central California.